Optical RF self-interference cancellation for full-duplex communication using an integrated DP-MZM

Abstract

An optical approach to implement the RF self-interference cancellation for Full-Duplex communication using an integrated dual-parallel Mach-Zehnder modulator (DP-MZM) is proposed and demonstrated experimentally. The received signals and the reference signal are converted into optical domain via the sub-MZMs (MZM1 and MZM2) in the DP-MZM, which are biased at the quadrature point and the minimum point with the output of double sideband with carrier (DSB + C) signal and double sideband with carrier-suppressed (DSB-CS) signal, respectively. It avoids the optical interference at the combining Y branch waveguide. The time and the amplitude matching conditions for cancellation between the reference signal and the interference signal are completed by the electrical tunable time delay line and the phase shifter in the MZM2 path. RF self-interference cancellation for single frequency and microwave with bandwidths of 20 MHz and 50 MHz is experimentally demonstrated to verify the proposed technique.